Can I undelegate in the middle of the delegation period?

You can choose to undelegate your SKL tokens at any time but the undelegation will not take effect until after the initial 60-day Proof of Use delegation period is over and the set of tokens are unlocked.

Once delegated, the delegation period must be completed before the delegation lock ends and tokens become transferable.

By way of example, if tokens are delegated in time for the Oct 1 epoch (or the first day of any delegation period), the token holder can send an undelegation request at any time prior to the end of the delegation period. Upon completion of the Proof of Use period (or any delegation period), the tokens will be unlocked and undelegated.